1. Field of the Invention
The present invention relates to an ultrasonic sensor assembly, which is installed to an installation object, such as a bumper of a vehicle, to sense presence of an obstacle.
2. Description of Related Art
A structure for installing the ultrasonic sensor apparatus, which senses presence of an obstacle, to the bumper of the vehicle is recited in Japanese Unexamined Patent Publication Number 2001-66359.
In Japanese Unexamined Patent Publication Number 2001-66359, a through hole is formed through the bumper (support body), and an ultrasonic sensor apparatus (an ultrasonic sensing device) is received in the through hole from an outer surface side of the bumper in such a manner that one end of the ultrasonic sensor apparatus contacts an peripheral edge of an opening of the through hole on the outer surface of the bumper. One coil spring (a resilient member) is provided to the ultrasonic sensor apparatus in such a manner that a portion of the ultrasonic sensor apparatus is received in the coil spring, and the coil spring is resiliently deformed between the ultrasonic sensor apparatus and the bumper. The bumper is clamped between the coil spring and one end of the ultrasonic sensor apparatus, which contacts the edge of the opening of the through hole on the outer surface of the bumper, to secure the ultrasonic sensor apparatus to the bumper.
However, in the above construction, the ultrasonic sensor apparatus is secured to the bumper by inserting the ultrasonic sensor apparatus in the through hole of the bumper from the outer surface side of the bumper. Thus, the structure of the ultrasonic sensor apparatus is limited by geometrical limitations, such as a size and a shape, of the through hole of the bumper. In other words, there is less freedom in designing of the ultrasonic sensor apparatus.
Furthermore, the bumper is clamped through use of the single coil spring, which is configured to receive the portion of the ultrasonic sensor apparatus. Thus, when one or more of a wall thickness of the bumper, an R (radius) of the bumper, an angle of the bumper relative to the ultrasonic sensor apparatus changes, the bumper cannot be uniformly held by the single coil spring. This causes chattering between the bumper and the ultrasonic sensor apparatus.
The present invention addresses the above disadvantages. Thus, it is an objective of the present invention to provide an ultrasonic sensor assembly, which includes an ultrasonic sensor apparatus and increases design freedom of the ultrasonic sensor apparatus while providing more uniform holding capability for holding an installation object, to which the ultrasonic sensor assembly is installed.
To achieve the objective of the present invention, there is provided an ultrasonic sensor assembly that is installable to a through hole of an installation object, which extends from a first surface to a second surface of the installation object. The ultrasonic sensor assembly includes an ultrasonic sensor apparatus, a holding member and a plurality of spring portions. The ultrasonic sensor apparatus includes a sensor arrangement and a housing. The sensor arrangement is held by the housing and is received in the through hole of the installation object upon installation of the ultrasonic sensor assembly to the installation object. The holding member holds the ultrasonic sensor apparatus relative to the installation object. The holding member includes a flange portion and a holding portion. The flange portion is secured to the first surface of the installation object around a peripheral edge of the through hole of the installation object upon the installation of the holding member to the installation object. The holding portion is connected to the flange portion and extends through the through hole of the installation object upon the installation of the holding member to the installation object, so that the holding portion projects from the second surface of the installation object. The spring portions are partially secured to the housing of the ultrasonic sensor apparatus and are resiliently deformed between the housing and the second surface of the installation object. The spring portions and the flange portion cooperate together to clamp the installation object therebetween.